A high gloss paint will show all defects so I would not do this if you don' t have a great surface to work with.

When we remove it, if we discover a leak at the bottom of the tank, could it result in much higher expenses than a surface leak because the oil could have seeped into the ground and be very expensive to fix?

I been approached on occasions to get involved in business propositions that look great on the surface, but just didn't sit right for me after doing the my due diligence.

My gut tells me that we have not even began to scratch the surface in this two hour session let alone be ready for deals, yet that is how most of these guys presumably got started.  

The landlord is in violation of city code which states that "No basement may be used as a habitable room unless floors and walls are impervious to leakage of underground and surface run-off water."

The pros are: Looks nice, easy to put in, you can replace a piece later if it gets jacked up, you can install over almost any surface.

I'm just starting to scratch the surface on investing.

This may cost a little more than just a surface cleaning but you need to show a good faith effort.  

What we discovered was that the house has a floating slab so there is a small channel around the whole thing which would normally catch any moisture and either route it to the floor drain or let it evaporate but in this case was used to feed moisture directly to the finished surfaces.

Cracks in the basement walls mostly and uneven surfaces if the property is on a slab.